@mediocre, I get the impression that you're frustrated and blame will help discharge it. But I think you're sending it in the wrong direction.
In the OP, you asked the American forum members, "Why do you do this?" I think because you think we have some agency and control.
We don't.
It is a system set up to ostensibly represent and support us, but it does not. It represents and supports its own interests. We have no choice but to play the games we don't choose to be in. Personally, I stopped playing what I could.
We don't have an impact in the general election for president. The electoral college overrides the popular vote. That's why Trump is president. That's why Bush was president. I stopped voting. I stopped playing. I don't participate in something that is a total waste of my energy. Some countries actually force citizens to participate in the illusions and vote, so I guess I can count myself fortunate that I'm given enough supposed freedom to not have to.
It all sucks, and I don't know who is to blame. Would that I did. But it's not the people. It not the citizens. We are not stupid, we just don't have power. It's falsely empowering to us to blame us, which is what victim blaming does. It gives more power to those who don't merit having it and who abuse it.
Trump was overtly abusive to women and ethnic "minorities," and broke tax laws at the least. Biden has also been abusive to women, for starters. Yet someone higher than the individual citizens decides they are our only choices.
It's all illusion that we have rights and power. It's a tasty myth, and sneakily corrosive and disempowering. Just like imperial and colonial powers, it generates admiration and agreement in order to falsely validate and reinforce abusive powers. Anyone who goes against it is at best laughed at, derided, or ignored, or at worst, crushed, along with anyone who dared to support them. Abusive governmental power functioning in this way is nothing new. It is all self-reifying manipulation and, when needed, overt and violent control. Machiavelli laid it all it out quite well, as did Lao Tzu, with a bit more moral ethics. Michel Foucault laid it out less clearly but quite comprehensively in several books and lectures.
In short: moral ethics are not valued by power structures, because they are not run by Marcus Aureliuses. They don't use their power to serve, but to be served. Gautama Buddha said that one sentence is the root of all violence and oppression: "I have power, and I want power." I think it's possible that you see the oppressed as having agency and freedom because of the feel-good myths propogated by the US Constitution, which is not upheld in practice, and therefore erroneously assign too much power to the oppressed. Blaming us just reinforces the oppression on us by giving credence to the myths.